In this post, we are going to discuss the element types in Hypermesh used for meshing.
Now that we understand what is meshing, it is time to get familiar with how we mesh geometries, i.e. the types of elements we use to cover the geometries.
The types of elements used in meshing are divided into three categories according to the number of relevant dimensions:
- 1D elements – bar, beam, rod, spring, gap, rigid
- 2D elements – trias, R-trias, Quad, mixed
- 3D elements – Tetra, Pyramid, Prism, Hex
1D and 2D elements are self-explanatory. However, 3D elements can be a bit complex to understand.
The white color lines in the above images are the edges of the element and the orange color dots are the nodes.
One question that might arise after seeing the above images is the types of 1D elements mentioned above are more but the only possible element which can be created in 1D is a line. Then how do we differentiate between the different types of 1D elements? The differentiation lies in the type of response they can produce, i.e., rod elements support only tension and compression, beam elements support bending as well as tension and compression, etc.
We will start with tetra elements; they contain 4 nodes in total with 3 nodes forming a triangle in the base as shown in the above image. Then comes Pyramid which contains 5 nodes in total of which 4 nodes form a rectangular base. After this we have Prism, which contains 6 nodes in total of which 4 nodes form a rectangular base and the 2 nodes form 2 triangles. Then at last we have Hex which contains 8 nodes which is basically the extruded version of the quad element.
Refer to the below video for better visualization of 2D and 3D elements.
Now the important thing is to understand when we should use which type of element.
We use 1D elements when one of the dimensions is very large in comparison with the other two dimensions of the body. Similarly, we use 2D elements when two dimensions are very large in comparison with respect to the third dimension, namely thickness. When all the dimensions are comparable, we use 3D elements.
Another classification for elements is based on their order, according to which they are classified as follows.
- First Order – In these types of elements the nodes are only present on the corners of the element.
- Second Order – In these types of elements the nodes are not only present on the corners but in the middle of the edges too.
In the next post, we will discuss where we use 2D and 3D elements. Till then keep learning. Don’t forget to follow my Facebook and Instagram pages for regular updates. See you all.